Automatic transmission device

ABSTRACT

An automatic transmission configured with four planetary gear mechanisms, three clutches, and three brakes, which are configured to provide nine forward speeds and a reverse speed. The combination of elements results in, amongst other benefits, improved torque transfer efficiency. A first planetary gear mechanism including first to third rotary elements that form a sequence of the first rotary element, the second rotary element, and the third rotary element when arranged in an order at intervals corresponding to gear ratios in a velocity diagram. A second planetary gear mechanism including fourth to sixth rotary elements, a third planetary gear mechanism including seventh to ninth rotary elements, and a fourth planetary gear mechanism including tenth to twelfth rotary elements.

TECHNICAL FIELD

The present invention relates to an automatic transmission device thatchanges the speed of power input to an input member to output the powerto an output member.

BACKGROUND ART

Hitherto, there has been proposed an automatic transmission devicecapable of establishing nine forward speeds and a reverse speed withfour planetary gear mechanisms, three clutches, and three brakes (seePatent Document 1, for example). The configuration of the device isillustrated in FIG. 5. As illustrated in the drawing, an automatictransmission device 901 according to a conventional example as thebackground art includes single-pinion first to fourth planetary gearmechanisms 910, 920, 930, and 940 each composed of a sun gear 911, 921,931, or 941 which is an externally toothed gear, a ring gear 913, 923,933, or 943 which is an internally toothed gear, and a carrier 912, 922,932, and 942 that rotatably and revolvably holds a plurality of piniongears 914, 924, 934, and 944 by coupling the pinion gears 914, 924, 934,and 944 to each other, respectively. The sun gear 911 and the sun gear921 are coupled to each other by a first coupling element 951. The ringgear 913 and the carrier 922 are coupled to each other by a secondcoupling element 952. The ring gear 923, the carrier 932, and thecarrier 942 are coupled to each other by a third coupling element 953.The fourth planetary gear mechanism 940 is formed on the outerperipheral side of the third planetary gear mechanism 930. The ring gear933 and the sun gear 941 are coupled to each other by a fourth couplingelement 954. The sun gear 931 is connected to an input shaft 903 via aclutch C901, and connected to a case 902 via a brake B901. The secondcoupling element 952 is connected to the input shaft 903 via a clutchC902. Further, the fourth coupling element 954 is connected to the inputshaft 903 via a dog clutch DC. The first coupling element 951 isconnected to the case 902 via a dog brake DB. The ring gear 943 of thefourth planetary gear mechanism 940 is connected to the case 902 via abrake B902. An output gear 904 is connected to the carrier 912 of thefirst planetary gear mechanism 910.

In the automatic transmission device 901 according to the conventionalexample, the gear ratios λ1, λ2, λ3, and λ4 of the first to fourthplanetary gear mechanisms 910, 920, 930, and 940 (the number of teeth ofthe sun gear/the number of teeth of the ring gear in each of theplanetary gear mechanisms) are set to 0.36, 0.36, 0.56, and 0.66,respectively. As illustrated in the operation table of FIG. 6, a firstforward speed to a ninth forward speed and a reverse speed areestablished, and the gear ratio width which is calculated as the gearratio of the first forward speed (lowest speed)/the gear ratio of theninth forward speed (highest speed) is 10.02.

In the automatic transmission device 901 according to the conventionalexample, in addition, with the ninth forward speed which is the highestspeed established, the clutch C901, the clutch C902, and the brake B902are engaged, and the dog clutch DC, the dog brake DB, and the brake B901are disengaged. Thus, all (four) of the first to fourth planetary gearmechanisms 910, 920, 930, and 940 operate as a gear mechanism for torquetransfer from the input shaft 903 to the output gear 904. With theeighth forward speed which is one step lower than the highest speedestablished, meanwhile, the clutch C902, the brake B901, and the brakeB902 are engaged, and the clutch C901, the dog clutch DC, and the dogbrake DB are disengaged. Thus, two of the planetary gear mechanisms,namely the first planetary gear mechanism 910 and the second planetarygear mechanism 920, operate as a gear mechanism for torque transfer fromthe input shaft 903 to the output gear 904.

RELATED-ART DOCUMENTS Patent Documents

-   [Patent Document 1] Published Japanese Translation of PCT    Application No. 2011-513662 (JP 2011-513662 A)

SUMMARY OF THE INVENTION

In such an automatic transmission device, in the case where an automatictransmission is composed of four planetary gear mechanisms and aplurality of clutches and brakes, there are a large number of manners toconnect the rotary elements of the four planetary gear mechanisms and toattach the plurality of clutches and brakes, and the device can functionas or cannot function as an automatic transmission device depending onthe manner of connection or attachment. In addition, if the number ofplanetary gear mechanisms that operate for torque transfer from theinput side to the output side at the highest forward speed or a shiftspeed that is one step lower than the highest forward speed is smaller,a loss due to meshing between gears is reduced, which enhances thetorque transfer efficiency.

It is a main object of the present invention to propose a new automatictransmission device with four planetary gear mechanisms, three clutches,and three brakes. It is a further object of the present invention toimprove the torque transfer efficiency.

In order to achieve at least the foregoing main object, the automatictransmission device according to the present invention adopts thefollowing means.

The present invention provides

an automatic transmission device that changes a speed of power input toan input member to output the power to an output member, characterizedby including:

a first planetary gear mechanism including first to third rotaryelements that form a sequence of the first rotary element, the secondrotary element, and the third rotary element when arranged in an orderat intervals corresponding to gear ratios in a velocity diagram;

a second planetary gear mechanism including fourth to sixth rotaryelements that form a sequence of the fourth rotary element, the fifthrotary element, and the sixth rotary element when arranged in an orderat intervals corresponding to gear ratios in a velocity diagram;

a third planetary gear mechanism including seventh to ninth rotaryelements that form a sequence of the seventh rotary element, the eighthrotary element, and the ninth rotary element when arranged in an orderat intervals corresponding to gear ratios in a velocity diagram;

a fourth planetary gear mechanism including tenth to twelfth rotaryelements that form a sequence of the tenth rotary element, the eleventhrotary element, and the twelfth rotary element when arranged in an orderat intervals corresponding to gear ratios in a velocity diagram;

a first coupling element that couples the first rotary element and theseventh rotary element to each other;

a second coupling element that couples the third rotary element and theeleventh rotary element to each other;

a third coupling element that couples the fifth rotary element, theninth rotary element, and the tenth rotary element to each other;

a first clutch that engages and disengages the second rotary element andthe third coupling element with and from each other;

a second clutch that engages and disengages the eighth rotary elementand the input member with and from each other;

a third clutch that engages and disengages the fourth rotary element andthe twelfth rotary element with and from each other;

a first brake that is disengageably engaged so as to hold the firstcoupling element stationary with respect to an automatic transmissiondevice case;

a second brake that is disengageably engaged so as to hold the eighthrotary element stationary with respect to the automatic transmissiondevice case; and

a third brake that is disengageably engaged so as to hold the twelfthrotary element stationary with respect to the automatic transmissiondevice case, in which:

the input member is connected to the sixth rotary element; and

the output member is connected to the second rotary element.

The automatic transmission device according to the present inventionincludes: the first planetary gear mechanism including as three rotaryelements the first to third rotary elements which form a sequence of thefirst rotary element, the second rotary element, and the third rotaryelement when arranged in an order at intervals corresponding to gearratios in a velocity diagram; the second planetary gear mechanismincluding as three rotary elements the fourth to sixth rotary elementswhich form a sequence of the fourth rotary element, the fifth rotaryelement, and the sixth rotary element when arranged in an order atintervals corresponding to gear ratios in a velocity diagram; the thirdplanetary gear mechanism including as three rotary elements the seventhto ninth rotary elements which form a sequence of the seventh rotaryelement, the eighth rotary element, and the ninth rotary element whenarranged in an order at intervals corresponding to gear ratios in avelocity diagram; and the fourth planetary gear mechanism including asthree rotary elements the tenth to twelfth rotary elements which form asequence of the tenth rotary element, the eleventh rotary element, andthe twelfth rotary element when arranged in an order at intervalscorresponding to gear ratios in a velocity diagram, and the first rotaryelement and the seventh rotary element are coupled to each other by thefirst coupling element, the third rotary element and the eleventh rotaryelement are coupled to each other by the second coupling element, andthe fifth rotary element, the ninth rotary element, and the tenth rotaryelement are coupled to each other by the third coupling element. Then,the second rotary element and the third coupling element are connectedto each other via the first clutch, the eighth rotary element and theinput member are connected to each ether via the second clutch, thefourth rotary element and the twelfth rotary element are connected toeach other via the third clutch, the first brake is connected to thefirst coupling element, the second brake is connected to the eighthrotary element, the third brake is connected to the twelfth rotaryelement, the input member is connected to the sixth rotary element, andthe output member is connected to the second rotary element. This makesit possible to constitute an automatic transmission device that canfunction with the four planetary gear mechanisms, the three clutches,and the three brakes.

In the thus configured automatic transmission device according to thepresent invention, a first forward speed to a ninth forward speed and areverse speed may be established as follows:

(1) The first forward speed is established by engaging the third clutch,the first brake, and the third brake and disengaging the first clutch,the second clutch, and the second brake.

(2) The second forward speed is established by engaging the secondclutch, the first brake, and the third brake and disengaging the firstclutch, the third clutch, and the second brake.

(3) The third forward speed is established by engaging the secondclutch, the third clutch, and the third brake and disengaging the firstclutch, the first brake, and the second brake.

(4) The fourth forward speed is established by engaging the firstclutch, the second clutch, and the third brake and disengaging the thirdclutch, the first brake, and the second brake.

(5) The fifth forward speed is established by engaging the first clutch,the third clutch, and the third brake and disengaging the second clutch,the first brake, and the second brake.

(6) The sixth forward speed is established by engaging the first clutch,the second clutch, and the third clutch and disengaging the first brake,the second brake, and the third brake.

(7) The seventh forward speed is established by engaging the firstclutch, the third clutch, and the first brake and disengaging the secondclutch, the second brake, and the third brake.

(8) The eighth forward speed is established by engaging the firstclutch, the second clutch, and the first brake and disengaging the thirdclutch, the second brake, and the third brake.

(9) The ninth forward speed is established by engaging the secondclutch, the third clutch, and the first brake and disengaging the firstclutch, the second brake, and the third brake.

(10) The reverse speed is established by engaging the third clutch, thesecond brake, and the third brake and disengaging the first clutch, thesecond clutch, and the first brake.

Consequently, there can be provided a device capable of selectivelyestablishing a first forward speed to a ninth forward speed and areverse speed with the four planetary gear mechanisms, the threeclutches, and the three brakes.

As discussed above, with the ninth forward speed which is the highestspeed established, the second clutch, the third clutch, and the firstbrake are engaged, and the first clutch, the second brake, and the thirdbrake are disengaged. Therefore, with the ninth forward speedestablished, all of the four planetary gear mechanisms operate as a gearmechanism for torque transfer between the input member and the outputmember. With the eighth forward speed which is one step lower than thehighest speed established, on the other hand, the first clutch, thesecond clutch, and the first brake are engaged, and the third clutch,the second brake, and the third brake are disengaged. At this time,torque input to the input member is output to the output member via theeighth rotary element and the ninth rotary element of the thirdplanetary gear mechanism and the third coupling element. Thus, with theeighth forward speed established, only one of the planetary gearmechanisms, namely the third planetary gear mechanism, operates as agear mechanism for torque transfer between the input member and theoutput member. As seen from the foregoing description, the number ofplanetary gear mechanisms that operate as a gear mechanism for torquetransfer between the input member and the output member is four with theninth forward speed which is the highest speed established, and one withthe eighth forward speed which is one step lower than the highest speedestablished, and thus the number of planetary gear mechanisms thatoperate as a gear mechanism for torque transfer can be reduced comparedto the automatic transmission device according to the conventionalexample, in which the number of planetary gear mechanisms that operateas a gear mechanism for torque transfer is four with the ninth forwardspeed which is the highest speed established, and two with the eighthforward speed which is one step lower than the highest speedestablished. This makes it possible to reduce a loss due to meshingbetween gears, and to enhance the torque transfer efficiency. That is,the torque transfer efficiency can be improved compared to the automatictransmission device according to the conventional example.

In the automatic transmission device according to the present inventiondiscussed above, the first planetary gear mechanism, the secondplanetary gear mechanism, the third planetary gear mechanism, and thefourth planetary gear mechanism may each be constituted as asingle-pinion; planetary gear mechanism in which a sun gear, a ringgear, and a carrier are used as the three rotary elements; the firstrotary element, the fourth rotary element, the seventh rotary element,and the tenth rotary element may each be a sun gear; the second rotaryelement, the fifth rotary element, the eighth rotary element, and theeleventh rotary element may each be a carrier; and the third rotaryelement, the sixth rotary element, the ninth rotary element, and thetwelfth rotary element may each be a ring gear.

In the automatic transmission device according to the present invention,further, the fourth planetary gear mechanism may be provided on an outerperipheral side of the third planetary gear mechanism. Consequently,although the automatic transmission device is made larger in the radialdirection, the automatic transmission device can be made shorter in theaxial direction. That is, the automatic transmission device can have thesame length in the axial direction as that of an automatic transmissiondevice with three planetary gear mechanism.

In the automatic transmission device according to the present invention,the planetary gear mechanisms may be disposed in an order of the secondplanetary gear mechanism, the third planetary gear mechanism and thefourth planetary gear mechanism, and the first planetary gear mechanism.

In the automatic transmission device according to the present invention,the third brake may be constituted as a dog brake. The dog brake tendsto cause a shock during engagement, and requires synchronization controlfor synchronizing rotations. Because the third brake is kept engagedfrom the first forward speed to the fifth forward speed and keptdisengaged from the sixth forward speed to the ninth forward speed, thethird brake is not frequently repeatedly engaged and disengaged, and thesynchronization control is less frequently performed. Therefore,degradation in shifting feeling is suppressed even if the dog brake isadopted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a schematic configuration of anautomatic transmission device 1 according to an embodiment.

FIG. 2 is an operation table of the automatic transmission device 1.

FIG. 3 is a velocity diagram of the automatic transmission device 1.

FIG. 4 is a diagram illustrating a schematic configuration of anautomatic transmission device 1B according to a modification.

FIG. 5 is a diagram illustrating a schematic configuration of anautomatic transmission device 901 according to a conventional example.

FIG. 6 is an operation table of the automatic transmission device 901according to the conventional example.

MODES FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below.

FIG. 1 is a diagram illustrating a schematic configuration of anautomatic transmission device 1 according to an embodiment of thepresent invention. The automatic transmission device 1 according to theembodiment is constituted as a stepped speed change mechanism thatincludes four single-pinion planetary gear mechanisms 10, 20, 30, and40, three clutches C1 to C3, and three brakes B1 to B3, that is mountedon a vehicle of a type (for example, a front-engine front-drive type) inwhich an engine as an internal combustion engine (not illustrated) isdisposed transversely (in the left-right direction of the vehicle), andthat receives power from the engine through an input shaft 3 via astarting device such as a torque converter (not illustrated) and changesthe speed of the input power to output the power to an output gear 4.The power output to the output gear 4 is output to left and right drivewheels 7 a and 7 b via a gear mechanism 5 and a differential gear 6. Thegear mechanism 5 is constituted from a counter shaft 5 a having arotational axis disposed in parallel with the rotational axis of theoutput gear 4, a counter driven gear 5 b attached to the counter shaft 5a and meshed with the output gear 4, and a differential drive gear 5 calso attached to the counter shaft 5 a and meshed with a ring gear ofthe differential gear 6. In the lower part of FIG. 1 with respect to theinput shaft 3, the connection between the output gear 4 and the gearmechanism 5, among components of the automatic transmission device 1, ismainly illustrated, and some of the other components are notillustrated.

In the automatic transmission device 1 according to the embodiment, asillustrated in FIG. 1, the second planetary gear mechanism 20, the thirdplanetary gear mechanism 30 and the fourth planetary gear mechanism. 40,and the first planetary gear mechanism 10 are disposed in this orderfrom the input shaft 3 side. The fourth planetary gear mechanism 40 isdisposed on the outer peripheral side of the third planetary gearmechanism 30.

The first planetary gear mechanism 10 includes a sun gear 11 which is anexternally toothed gear, a ring gear 13 which is an internally toothedgear disposed concentrically with the sun gear 11, a plurality of piniongears 14 meshed with the sun gear 11 and meshed with the ring gear 13,and a carrier 12 that rotatably and revolvably holds the plurality ofpinion gears 14 by coupling the pinion gears 14 to each other. The firstplanetary gear mechanism 10 is constituted as single-pinion planetarygear mechanism. Thus, the three rotary elements, namely the sun gear 11,the ring gear 13, and the carrier 12, form a sequence of the sun gear11, the carrier 12, and the ring gear 13 when arranged in the order atintervals corresponding to the gear ratios in the velocity diagram. Thegear ratio λ1 of the first planetary gear mechanism 10 (the number ofteeth of the sun gear 11/the number of teeth of the ring gear 13) is setto 0.35, for example.

The second planetary gear mechanism 20 includes a sun gear 21 which isan externally toothed gear, a ring gear 23 which is an internallytoothed gear disposed concentrically with the sun gear 21, a pluralityof pinion gears 24 meshed with the sun gear 21 and meshed with the ringgear 23, and a carrier 22 that rotatably and revolvably holds theplurality of pinion gears 24 by coupling the pinion gears 24 to eachother. The second planetary gear mechanism 20 is constituted as asingle-pinion planetary gear mechanism. Thus, the three rotary elements,namely the sun gear 21, the ring gear 23, and the carrier 22, form asequence of the sun gear 21, the carrier 22, and the ring gear 23 whenarranged in the order at intervals corresponding to the gear ratios inthe velocity diagram. The gear ratio λ2 of the second planetary gearmechanism 20 (the number of teeth of the sun gear 21/the number of teethof the ring gear 23) is set to 0.25, for example.

The third planetary gear mechanism 30 includes a sun gear 31 which is anexternally toothed gear, a ring gear 33 which is an internally toothedgear disposed concentrically with the sun gear 31, a plurality of piniongears 34 meshed with the sun gear 31 and meshed with the ring gear 33,and a carrier 32 that rotatably and revolvably holds the plurality ofpinion gears 34 by coupling the pinion gears 34 to each other. The thirdplanetary gear mechanism 30 is constituted as a single-pinion planetarygear mechanism. Thus, the three rotary elements, namely the sun gear 31,the ring gear 33, and the carrier 32, form a sequence of the sun gear31, the carrier 32, and the ring gear 33 when arranged in the order atintervals corresponding to the gear ratios in the velocity diagram. Thegear ratio λ3 of the third planetary gear, mechanism 30 (the number ofteeth of the sun gear 31/the number of teeth of the ring gear 33) is setto 0.45, for example.

The fourth planetary gear mechanism 40 includes a sun gear 41 which isan externally toothed gear, a ring gear 43 which is an internallytoothed gear disposed concentrically with the sun gear 41, a pluralityof pinion gears 44 meshed with the sun gear 41 and meshed with the ringgear 43, and a carrier 42 that rotatably and revolvably holds theplurality of pinion gears 44 by coupling the pinion gears 44 to eachother. The fourth planetary gear mechanism 40 is constituted as, asingle-pinion planetary gear mechanism. Thus, the three rotary elements,namely the sun gear 41, the ring gear 43, and the carrier 42, form asequence of the sun gear 41, the carrier 42, and the ring gear 43 whenarranged in the order at intervals corresponding to the gear ratios inthe velocity diagram. The gear ratio λ4 of the fourth planetary gearmechanism 40 (the number of teeth of the sun gear 41/the number of teethof the ring gear 43) is set to 0.60, for example.

The sun gear 11 of the first planetary gear mechanism 10 is coupled tothe sun gear 31 of the third planetary gear mechanism 30 by a firstcoupling element 51. The ring gear 13 of the first planetary gearmechanism 10 is coupled to the carrier 42 of the fourth planetary gearmechanism 40 by a second coupling element 52. In addition, the carrier22 of the second planetary gear mechanism 20 is coupled to the ring gear33 of the third planetary gear mechanism 30 and the sun gear 41 of thefourth planetary gear mechanism 40 by a third coupling element 53. Inthe automatic transmission device 1 according to the embodiment, asdiscussed above, the fourth planetary gear mechanism 40 is disposed onthe outer peripheral side of the third planetary gear mechanism 30. Thatis, an externally toothed gear is formed on the outer peripheral side ofthe ring gear 33 of the third planetary gear mechanism 30 to be used asthe sun gear 41 of the fourth planetary gear mechanism 40, and the ringgear 33, the third coupling element 53, and the sun gear 41 are formedintegrally with each other. Thus, the third coupling element 53 servesan element that couples the ring gear 33 and the sun gear 41 of thefourth planetary gear mechanism 40 in the radial direction on the outerperipheral side of the ring gear 33 which is positioned on the outermostperiphery of the third planetary gear mechanism 30, and also serves asan element that couples the ring gear 33, the sun gear 41, and thecarrier 22 of the second planetary gear mechanism 20.

The third coupling element 53 (the carrier 22, the ring gear 33, the sungear 41) of the automatic transmission device 1 according to theembodiment is connected to the carrier 12 of the first planetary gearmechanism 10 via the clutch C1. The carrier 32 of the third planetarygear mechanism 30 is connected to the ring gear 23 of the secondplanetary gear mechanism 20 via the clutch C2. In addition, the sun gear21 of the second planetary gear mechanism 20 is connected to the ringgear 43 of the fourth planetary gear mechanism 40 via the clutch C3. Thefirst coupling element 51 (the sun gear 11, the sun gear 31) isconnected to a case (automatic transmission device case) 2 via the brakeB1. The carrier 32 of the third planetary gear mechanism 30 is connectedto the case 2 via the brake B2. In addition, the ring gear 43 of thefourth planetary gear mechanism 40 is connected to the case 2 via thebrake B3. The input shaft 3 is connected to the ring gear 23 of thesecond planetary gear mechanism 20. The output gear 4 is connected tothe carrier 12 of the first planetary gear mechanism 10. Here, in theembodiment, the three clutches C-1 to C-3 and the three brakes B-1 toB-3 are constituted as hydraulically driven friction clutches andfriction brakes that are engaged by pressing friction plates using apiston.

The thus configured automatic transmission device 1 according to theembodiment can switchably establish a first forward speed to a ninthforward speed and a reverse speed by engaging and disengaging the threeclutches C1 to C3 and engaging and disengaging the three brakes B1 to B3in combination. FIG. 2 is an operation table of the automatictransmission device 1. FIG. 3 includes velocity diagrams of the first tofourth planetary gear mechanisms 10, 20, 30, and 40 of the automatictransmission device 1. In FIG. 3, the velocity diagram of the firstplanetary gear mechanism 10, the velocity diagram of the secondplanetary gear mechanism 20, the velocity diagram of the third planetarygear mechanism 30, and the velocity diagram of the fourth planetary gearmechanism 40 are arranged in this order from the left. In each of thevelocity diagrams, the sun gear, the carrier, and the ring gear arearranged in this order from the left. In FIG. 3, in addition, “1st”indicates the first forward speed, “2nd” indicates the second forwardspeed, “3rd” indicates the third forward speed, “4th” to “9th” indicatethe fourth forward speed to the ninth forward speed, and “Rev” indicatesthe reverse speed. “λ1” to “λ4” indicate the respective gear ratios ofthe planetary gear mechanisms. “B1”, “B2”, and “B3” indicate the brakesB1 to B3. “INPUT” indicates the position of connection of the inputshaft 3. “OUTPUT” indicates the position of connection of the outputgear 4.

In the automatic transmission device 1 according to the embodiment, asillustrated in FIG. 2, the first forward speed to the ninth forwardspeed and the reverse speed are established as follows. For the gearratio (the rotational speed of the input shaft 3/the rotational speed ofthe output gear 4), the gear ratios λ1, λ2, λ3, and λ4 of the first tofourth planetary gear mechanisms 10, 20, 30, and 40 are set to 0.35,0.25, 0.45, and 0.60, respectively.

(1) The first forward speed can be established by engaging the clutchC3, the brake B1, and the brake B3 and disengaging the clutch C1, theclutch C2, and the brake B2, and has a gear ratio of 4.500.

(2) The second forward speed can be established by engaging the clutchC2, the brake B1, and the brake B3 and disengaging the clutch (1, theclutch C3, and the brake B2, and has a gear ratio of 2.483.

(3) The third forward speed can be established by engaging the clutchC2, the clutch C3, and the brake B3 and disengaging the clutch C1, thebrake B1, and the brake B2, and has a gear ratio of 1.676.

(4) The fourth forward speed can be established by engaging the clutchC1, the clutch C2, and the brake B3 and disengaging the clutch C3, thebrake B1, and the brake B2, and has a gear ratio of 1.554.

(5) The fifth forward speed can be established by engaging the clutchC1, the clutch C3, and the brake B3 and disengaging the clutch C2, thebrake B1, and the brake B2, and has a gear ratio of 1.250.

(6) The sixth forward speed can be established by engaging the clutchC1, the clutch C2, and the clutch C3 and disengaging the brake B1, thebrake B2, and the brake B3, and has a gear ratio of 1.000.

(7) The seventh forward speed can be established by engaging the clutchC1, the clutch C3, and the brake B1 and disengaging the clutch C2, thebrake B2, and the brake B3, and has a gear ratio of 0.860.

(8) The eighth forward speed can be established by engaging the clutchC1, the clutch C2, and the brake B1 and disengaging the clutch C3, thebrake B2, and the brake B3, and has a gear ratio of 0.690. With theeighth forward speed established, torque from the input shaft 3 istransferred to the output gear 4 via the carrier 32 of the thirdplanetary gear mechanism 30, the ring gear 33, the third couplingelement 53, and the carrier 12. Thus, with the eighth forward speedestablished, only one of the planetary gear mechanisms, namely the thirdplanetary gear mechanism 30, operates as a gear mechanism for torquetransfer between the input shaft 3 and the output gear 4.

(9) The ninth forward speed can be established by engaging the clutchC2, the clutch C3, and the brake B1 and disengaging the clutch C1, thebrake B2, and the brake B3, and has a gear ratio of 0.524. With theninth forward speed established, all of the four planetary gearmechanisms 10, 20, 30, and 40 operate as a gear mechanism for torquetransfer between the input shaft 3 and the output gear 4.

(10) The reverse speed can be established by engaging the clutch C3, thebrake B2, and the brake B3 and disengaging the clutch C1, the clutch C2,and the brake B1, and has a gear ratio of −4.190.

In the automatic transmission device 1 according to the embodiment, withthe ninth forward speed which is the highest speed established, all ofthe four planetary gear mechanisms 10, 20, 30, and 40 operate as a gearmechanism for torque transfer between the input shaft 3 and the outputgear 4. With the eighth forward speed which is one step lower than thehighest speed established, however, only one of the planetary gearmechanisms, namely the third planetary gear mechanism 30, operates as agear mechanism for torque transfer between the input shaft 3 and theoutput gear 4. In the automatic transmission device 901 according to theconventional example illustrated in FIG. 5, on the other hand, with theninth forward speed which is the highest speed established, all of thefour planetary gear mechanisms 910, 920, 930, and 940 operate for torquetransfer between the input shaft 903 and the output gear 904. With theeighth forward speed which is one step lower than the highest speedestablished, two of the planetary gear mechanisms, namely the firstplanetary gear mechanism 910 and the second planetary gear mechanism920, operate for torque transfer between the input shaft 903 and theoutput gear 904. Thus, in the automatic transmission device 1 accordingto the embodiment, the number of planetary gear mechanisms that operatefor torque transfer with the eighth forward speed which is one steplower than the highest speed established is reduced compared to theautomatic transmission device 901 according to the conventional example.As a result, with the automatic transmission device 1 according to theembodiment, it is possible to reduce a loss due to meshing between gearsand enhance the torque transfer efficiency compared to the automatictransmission device 901 according to the conventional example. Thus,because the highest speed and a shift speed that is one step lower thanthe highest speed are used for travel at a relatively high speed, forexample cruising on a highway, in the case where the automatictransmission device 1 is mounted on a vehicle, it is possible to enhancethe torque transfer efficiency during travel at a relatively high speed,and to improve the fuel efficiency of the vehicle.

The rotational speeds of the rotary elements constituting the planetarygear mechanisms of the automatic transmission device 1 according to theembodiment in which the gear ratios λ1, λ2, λ3, and λ4 of the first tofourth planetary gear mechanisms 10, 20, 30, and 40 are set to 0.35,0.25, 0.45, and 0.60, respectively, and of the automatic transmissiondevice 901 according to the conventional example illustrated in FIG. 5will be discussed below.

(1) For the automatic transmission device, 1 according to theembodiment, the highest one of the rotational speeds of the three rotaryelements (the sun gear 11, 21, 31, or 41, the carrier 12, 22, 32, or 42,and the ring gear 13, 23, 33, or 43) constituting the first to fourthplanetary gear mechanisms 10, 20, 30, and 40 is about 3.3 times therotational speed of the input shaft 3. For the automatic transmissiondevice 901 according to the conventional example, however, the highestone of the rotational speeds is about 5.5 times the rotational speed ofthe input shaft 903. Thus, with the automatic transmission device 1according to the embodiment, it is possible to reduce the highest one ofthe rotational speeds of the rotary elements compared to the automatictransmission device 901 according to the conventional example. As aresult, the automatic transmission device 1 according to the embodimentcan improve the durability of the device and suppress a cost requiredfor heat treatment or surface treatment for ensuring durability comparedto the automatic transmission device 901 according to the conventionalexample.

(2) For the automatic transmission device 1 according to the embodiment,the highest one of the rotational speeds of the pinion gears 14, 24, 34,and 44 of the first to fourth planetary gear mechanisms 10, 20, 30, and40 is about 3.4 times the rotational speed of the input shaft 3. For theautomatic transmission device 901 according to the conventional example,however, the highest one of the rotational speeds of the pinion gears isabout 4.8 times the rotational speed of the input shaft 903. Thus, withthe automatic transmission device 1 according to the embodiment, it ispossible to reduce the highest one of the rotational speeds of thepinion gears 14, 24, 34, and 44 compared to the automatic transmissiondevice 901 according to the conventional example. With the first forwardspeed, with which the rotational speed of the input shaft 3 is high,established, in particular, the highest one of the rotational speeds ofthe pinion gears 14, 24, 34, and 44 of the first to fourth planetarygear mechanisms 10, 20, 30, and 40 in the automatic transmission device1 according to the embodiment is about 1.5 times the rotational speed ofthe input shaft 3. For the automatic transmission device 901 accordingto the conventional example, however, the highest one of the rotationalspeeds of the pinion gears is about 2.7 times the rotational speed ofthe input shaft 903. As a result, the automatic transmission device 1according to the embodiment can improve the durability of parts such asbearings and pinion side washers and suppress a cost required for heattreatment or surface treatment for ensuring durability compared to theautomatic transmission device 901 according to the conventional example.

(3) For the automatic transmission device 1 according to the embodiment,the highest one of the relative rotational speeds of the engagementelements (the clutches C1 to C3 and the brakes B1 to B3) is 3.3 timesthe rotational speed of the input shaft 3. For the automatictransmission device 901 according to the conventional example, however,the highest one of the relative rotational speeds is 5.5 times therotational speed of the input shaft 903. Thus, with the automatictransmission device 1 according to the embodiment, it is possible toreduce the highest one of the relative rotational speeds of theengagement elements compared to the automatic transmission device 901according to the conventional example. As a result, wet multi-plateclutches and wet multi-plate brakes which are normally used asengagement elements can be used for the automatic transmission device 1according to the embodiment, and it is possible to obtain goodcontrollability during shifting and reduce a shock during shiftingcompared to the automatic transmission device 901 according to theconventional example which uses dog clutches and dog brakes.

With the automatic transmission device 1 according to the embodimentdescribed above, there can be provided an automatic transmission deviceincluding the single-pinion first to fourth planetary gear mechanisms.10, 20, 30, and 40, the three clutches C1 to C3, and the three brakes B1to B3 and capable of selectively establishing the first forward speed tothe ninth forward speed and the reverse speed, in which: the sun gear 11of the first planetary gear mechanism 10 is coupled to the sun gear 31of the third planetary gear mechanism 30 by the first coupling element51; the ring gear 13 of the first planetary gear mechanism 10 is coupledto the carrier 42 of the fourth planetary gear mechanism 40 by thesecond coupling element 52; the carrier 22 of the second planetary gearmechanism 20 is coupled to the ring gear 33 of the third planetary gearmechanism 30 and the sun gear 41 of the fourth planetary gear mechanism40 by the third coupling element 53; the third coupling element 53 (thecarrier 22, the ring gear 33, the sun gear 41) is connected to thecarrier 12 of the first planetary gear mechanism 10 via the clutch C1;the carrier 32 of the third planetary gear mechanism 30 is connected tothe ring gear 23 of the second planetary gear mechanism 20, via theclutch C2; the sun gear 21 of the second planetary gear mechanism 20 isconnected to the ring gear 43 of the fourth planetary gear mechanism 40via the clutch C3; the first coupling element 51 (the sun gear 11, thesun gear 31) is connected to the case 2 via the brake B1; the carrier 32of the third planetary gear mechanism 30 is connected to the case 2 viathe brake B2; the ring gear 43 of the fourth planetary gear mechanism 40is connected to the case 2 via the brake B3; the ring gear 23 of thesecond planetary gear mechanism 20 is connected to the input shaft 3;and the carrier 12 of the first planetary gear mechanism 10 is connectedto the output gear 4.

In the automatic transmission device 1 according to the embodiment, withthe ninth forward speed which is the highest speed established, all ofthe four planetary gear mechanisms 10, 20, 30, and 40 operate as a gearmechanism as in the automatic transmission device 901 according to theconventional example. With the eighth forward speed which is one steplower than the highest speed established, however, only one of theplanetary gear mechanisms, namely the third planetary gear mechanism 30operates as a gear for torque transfer between the input shaft 3 and theoutput gear 4, and the number of planetary gear mechanisms that operatefor torque transfer with the eighth forward speed established is reducedcompared to the automatic transmission device 901 according to theconventional example, in which two of the planetary gear mechanisms,namely the first planetary gear mechanism 910 and the second planetarygear mechanism 920, operate for torque transfer. This makes it possibleto reduce a loss due to meshing between gears, and to enhance the torquetransfer efficiency. As a result, the torque transfer efficiency of theautomatic transmission device can be improved.

In the automatic transmission device 1 according to the embodiment, thefourth planetary gear mechanism 40 is disposed on the outer peripheralside of the third planetary gear mechanism 30. Thus, although theautomatic transmission device 1 is made larger in the radial direction,the automatic transmission device 1 can be made shorter in the axialdirection than an automatic transmission device in which four planetarygear mechanisms are disposed side by side. That is, the automatictransmission device 1 has the same length in the axial direction as thatof an automatic transmission device in which three planetary gearmechanisms are disposed side by side.

In the automatic transmission device 1 according to the embodiment, thehighest one of the rotational speeds of the three rotary elementsconstituting the first to fourth planetary gear mechanisms 10, 20, 30,and 40 is low compared to the automatic transmission device 901according to the conventional example. Thus, it is possible to improvethe durability of the device and suppress a cost required for heattreatment or surface treatment for ensuring durability compared to theautomatic transmission device 901 according to the conventional example.In the automatic transmission device 1 according to the embodiment, inaddition, the highest one of the rotational speeds of the pinion gears14, 24, 34, and 44 of the first to fourth planetary gear mechanisms 10,20, 30, and 40 is low compared to the automatic transmission device 901according to the conventional example. Thus, it is possible to improvethe durability of the device and suppress a cost required for heattreatment or surface treatment for ensuring durability. In the automatictransmission device 1 according to the embodiment, further, the highestone of the relative rotational speeds of the engagement elements is lowcompared to the automatic transmission device 901 according to theconventional example. Thus, wet multi-plate clutches and wet multi-platebrakes which are normally used as engagement elements can be used toobtain good controllability during shifting and reduce a shock duringshifting.

In the automatic transmission device 1 according to the embodiment, allof the three clutches C-1 to C-3 are constituted as friction clutches,and all of the three brakes B-1 to B-3 are constituted as frictionbrakes. However, some of the clutches and brakes may be constituted asdog clutches and dog brakes in place of the friction clutches and thefriction brakes. An automatic transmission device 1B according to amodification of the automatic transmission device 1, in which the brakeB3 is constituted as a dog brake, is illustrated in FIG. 4. Theoperation table and the velocity diagram of the automatic transmissiondevice 1B according to the modification are the same as those in FIGS. 2and 3. The dog brake tends to cause a shock during engagement, andrequires synchronization control for synchronizing rotations. Becausethe brake B3 is kept engaged from the first forward speed to the fifthforward speed and kept disengaged from the sixth forward speed to theninth forward speed, the brake B3 is not frequently repeatedly engagedand disengaged, and the synchronization control is less frequentlyperformed. Therefore, degradation in shifting feeling is suppressed evenif the dog brake is adopted.

In the automatic transmission device 1 according to the embodiment, thegear ratios λ1, λ2, λ3, and λ4 of the first to fourth planetary gearmechanisms 10, 20, 30, and 40 are set to 0.35, 0.25, 0.45, and 0.60,respectively. However, the gear ratios λ1, λ2, λ3, and λ4 are notlimited to such values.

In the automatic transmission device 1 according to the embodiment, allof the first to fourth planetary gear mechanisms 10, 20, 30, and 40 areconstituted as a single-pinion planetary gear mechanism. However, someor all of the first to fourth planetary gear mechanisms 10, 20, 30, and40 may be constituted as a double-pinion planetary gear mechanism.

The automatic transmission device 1 according to the embodiment is anautomatic transmission device capable of establishing the first forwardspeed to the ninth forward speed and the reverse speed by engaging threeof the three clutches C1 to C3 and the three brakes B1 to B3 anddisengaging the other three. However, the automatic transmission device1 may be an automatic transmission device capable of establishing eightspeeds excluding one speed from the nine speeds from the first forwardspeed to the ninth forward speed, or seven speeds or less excluding aplurality of speeds from the nine speeds, and the reverse speed.

Here, the correspondence between the main elements of the embodiment andthe main elements of the invention described in the “SUMMARY OF THEINVENTION” section will be described. In the embodiment, the input shaft3 corresponds to the “input member”. The output gear. 4 corresponds tothe “output member”. The first planetary gear mechanism 10 correspondsto the “first planetary gear mechanism”. The sun gear 11 corresponds tothe “first rotary element”. The carrier 12 corresponds to the “secondrotary element”. The ring gear 13 corresponds to the “third rotaryelement”. The second planetary gear mechanism 20 corresponds to the“second planetary gear mechanism”. The sun gear 21 corresponds to the“fourth rotary element”. The carrier 22 corresponds to the “fifth rotaryelement”. The ring gear 23 corresponds to the “sixth rotary element”.The third planetary gear mechanism 30 corresponds to the “thirdplanetary gear mechanism”. The sun gear 31 corresponds to the “seventhrotary element”. The carrier 32 corresponds to the “eighth rotaryelement”. The ring gear 33 corresponds to the “ninth rotary element”.The fourth planetary gear mechanism 40 corresponds to the “fourthplanetary gear mechanism”. The sun gear 41 corresponds to the “tenthrotary element”. The carrier 42 corresponds to the “eleventh rotaryelement”. The ring gear 43 corresponds to the “twelfth rotary element”.The first coupling element 51 corresponds to the “first couplingelement”. The second coupling element 52 corresponds to the “secondcoupling element”. The third coupling element 53 corresponds to the“third coupling element”. The clutch C1 corresponds to the “firstclutch”. The clutch C2 corresponds to the “second clutch”. The clutch C3corresponds to the “third clutch”. The brake B1 corresponds to the“first brake”. The brake B2 corresponds to the “second brake”. The brakeB3 corresponds to the “third brake”. The correspondence between the mainelements of the embodiment and the main elements of the inventiondescribed in the “SUMMARY OF THE INVENTION” section does not limit theelements of the invention described in the “SUMMARY OF THE INVENTION”section, because the embodiment, is an example given for the purpose ofspecifically describing the best mode for carrying out the inventiondescribed in the “SUMMARY OF THE INVENTION” section. That is, theinvention described in the “SUMMARY OF THE INVENTION” section should beconstrued on the basis of the description in that section, and theembodiment is merely a specific example of the invention described inthe “SUMMARY OF THE INVENTION” section.

While the best mode for carrying out the present invention has beendescribed above by way of an embodiment, it is a matter of course thatthe present invention is not limited to the embodiment in any way, andthat the present invention may be implemented in various forms withoutdeparting from the scope and sprit of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to the automatic transmission devicemanufacturing industry and so forth.

The invention claimed is:
 1. An automatic transmission device thatchanges a speed of power input to an input member to output the power toan output member, characterized by comprising: a first planetary gearmechanism including first to third rotary elements that form a sequenceof the first rotary element, the second rotary element, and the thirdrotary element when arranged in an order at intervals corresponding togear ratios; a second planetary gear mechanism including fourth to sixthrotary elements that form a sequence of the fourth rotary element, thefifth rotary element, and the sixth rotary element when arranged in anorder at intervals corresponding to gear ratios; a third planetary gearmechanism including seventh to ninth rotary elements that form asequence of the seventh rotary element, the eighth rotary element, andthe ninth rotary element when arranged in an order at intervalscorresponding to gear ratios; a fourth planetary gear mechanismincluding tenth to twelfth rotary elements that form a sequence of thetenth rotary element, the eleventh rotary element, and the twelfthrotary element when arranged in an order at intervals corresponding togear ratios; a first coupling element that couples the first rotaryelement and the seventh rotary element to each other; a second couplingelement that couples the third rotary element and the eleventh rotaryelement to each other; a third coupling element that couples the fifthrotary element, the ninth rotary element, and the tenth rotary elementto each other; a first clutch that engages and disengages the secondrotary element and the third coupling element with and from each other;a second clutch that engages and disengages the eighth rotary elementand the input member with and from each other; a third clutch thatengages and disengages the fourth rotary element and the twelfth rotaryelement with and from each other; a first brake that is configured toselectively hold the first coupling element stationary with respect toan automatic transmission device case; a second brake that is configuredto selectively hold the eighth rotary element stationary with respect tothe automatic transmission device case; and a third brake that isconfigured to selectively hold the twelfth rotary element stationarywith respect to the automatic transmission device case, wherein: theinput member is connected to the sixth rotary element; and the outputmember is connected to the second rotary element.
 2. The automatictransmission device according to claim 1, wherein the planetary gearmechanisms are disposed in an order of the second planetary gearmechanism, the third planetary gear mechanism and the fourth planetarygear mechanism, and the first planetary gear mechanism.
 3. The automatictransmission device according to claim 1, wherein the third brake isconstituted as a dog brake.
 4. The automatic transmission deviceaccording to claim 1, wherein the fourth planetary gear mechanism isprovided on an outer peripheral side of the third planetary gearmechanism.
 5. The automatic transmission device according to claim 4,wherein the planetary gear mechanisms are disposed in an order of thesecond planetary gear mechanism, the third planetary gear mechanism andthe fourth planetary gear mechanism, and the first planetary gearmechanism.
 6. The automatic transmission device according to claim 4,wherein the third brake is constituted as a dog brake.
 7. The automatictransmission device according to claim 1, wherein: the first planetarygear mechanism, the second planetary gear mechanism, the third planetarygear mechanism, and the fourth planetary gear mechanism are eachconstituted as a single-pinion planetary gear mechanism comprising a sungear, a ring gear, and a carrier; the first rotary element, the fourthrotary element, the seventh rotary element, and the tenth rotary elementare each a sun gear; the second rotary element, the fifth rotaryelement, the eighth rotary element, and the eleventh rotary element areeach a carrier; and the third rotary element, the sixth rotary element,the ninth rotary element, and the twelfth rotary element are each a ringgear.
 8. The automatic transmission device according to claim 7, whereinthe planetary gear mechanisms are disposed in an order of the secondplanetary gear mechanism, the third planetary gear mechanism and thefourth planetary gear mechanism, and the first planetary gear mechanism.9. The automatic transmission device according to claim 7, wherein thethird brake is constituted as a dog brake.
 10. The automatictransmission device according to claim 7, wherein the fourth planetarygear mechanism is provided on an outer peripheral side of the thirdplanetary gear mechanism.
 11. The automatic transmission deviceaccording to claim 10, wherein the planetary gear mechanisms aredisposed in an order of the second planetary gear mechanism, the thirdplanetary gear mechanism and the fourth planetary gear mechanism, andthe first planetary gear mechanism.
 12. The automatic transmissiondevice according to claim 1, wherein: a first forward speed isestablished by engaging the third clutch, the first brake, and the thirdbrake and disengaging the first clutch, the second clutch, and thesecond brake; a second forward speed is established by engaging thesecond clutch, the first brake, and the third brake and disengaging thefirst clutch, the third clutch, and the second brake; a third forwardspeed is established by engaging the second clutch, the third clutch,and the third brake and disengaging the first clutch, the first brake,and the second brake; a fourth forward speed is established by engagingthe first clutch, the second clutch, and the third brake and disengagingthe third clutch, the first brake, and the second brake; a fifth forwardspeed is established by engaging the first clutch, the third clutch, andthe third brake and disengaging the second clutch, the first brake, andthe second brake; a sixth forward speed is established by engaging thefirst clutch, the second clutch, and the third clutch and disengagingthe first brake, the second brake, and the third brake; a seventhforward speed is established by engaging the first clutch, the thirdclutch, and the first brake and disengaging the second clutch, thesecond brake, and the third brake; an eighth forward speed isestablished by engaging the first clutch, the second clutch, and thefirst brake and disengaging the third clutch, the second brake, and thethird brake; a ninth forward speed is established by engaging the secondclutch, the third clutch, and the first brake and disengaging the firstclutch, the second brake, and the third brake; and a reverse speed isestablished by engaging the third clutch, the second brake, and thethird brake and disengaging the first clutch, the second clutch, and thefirst brake.
 13. The automatic transmission device according to claim12, wherein the planetary gear mechanisms are disposed in an order ofthe second planetary gear mechanism, the third planetary gear mechanismand the fourth planetary gear mechanism, and the first planetary gearmechanism.
 14. The automatic transmission device according to claim 12,wherein the third brake is constituted as a dog brake.
 15. The automatictransmission device according to claim 12, wherein the fourth planetarygear mechanism is provided on an outer peripheral side of the thirdplanetary gear mechanism.
 16. The automatic transmission deviceaccording to claim claim 15, wherein the planetary gear mechanisms aredisposed in an order of the second planetary gear mechanism, the thirdplanetary gear mechanism and the fourth planetary gear mechanism, andthe first planetary gear mechanism.
 17. The automatic transmissiondevice according to claim 12, wherein: the first planetary gearmechanism, the second planetary gear mechanism, the third planetary gearmechanism, and the fourth planetary gear mechanism are each constitutedas a single-pinion planetary gear mechanism comprising a sun gear, aring gear, and a carrier; the first rotary element, the fourth rotaryelement, the seventh rotary element, and the tenth rotary element areeach a sun gear; the second rotary element, the fifth rotary element,the eighth rotary element, and the eleventh rotary element are each acarrier; and the third rotary element, the sixth rotary element, theninth rotary element, and the twelfth rotary element are each a ringgear.
 18. The automatic transmission device according to claim 17,wherein the planetary gear mechanisms are disposed in an order of thesecond planetary gear mechanism, the third planetary gear mechanism andthe fourth planetary gear mechanism, and the first planetary gearmechanism.
 19. The automatic transmission device according to claim 17,wherein the fourth planetary gear mechanism is provided on an outerperipheral side of the third planetary gear mechanism.
 20. The automatictransmission device according to claim 19, wherein the planetary gearmechanisms are disposed in an order of the second planetary gearmechanism, the third planetary gear mechanism and the fourth planetarygear mechanism, and the first planetary gear mechanism.